JP2008255497A - Steel cord for reinforcing rubber product and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel cord which is used for reinforcing rubber products, has good rubber material invasiveness, is free from the slip of a core strand group and an intermediate strand group, has a stable twist structure, is little extended with low loads, and has a three-layered structure. <P>SOLUTION: The cord 10 having an L+M+N structure is produced by twisting intermediate strands 12 each having smaller pitch approximately sine wave-like curls than the pitches of curls for twisting all strands, around a core strand 11, further twisting side strands 13, and then pressing in the direction crossing the longitudinal direction of the cord. A steel cord having a 1×P structure is produced by simultaneously twisting all intermediate strands each having a smaller pitch approximately sine wave-like curls than the pitches of curls for twisting the strands with other strands, and then pressing the twisted product. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a steel cord for reinforcing rubber products (hereinafter sometimes simply referred to as “cord”) used as a reinforcing material for rubber products such as automobile tires and conveyor belts.

  Conventionally, steel cords for reinforcing rubber products such as 1 + 6 + 12 structure, 3 + 9 + 15 structure, 1 × 19 structure, 1 × 27 structure, etc. used as a rubber product reinforcing material for automobile tires, conveyor belts, etc. A so-called closed twisted cord in which the strands of the book are tightly twisted and brought into close contact is generally used. However, this closed twisted cord has a closed cavity between adjacent strands, and when a composite sheet is formed by sandwiching the cord between two rubber sheets and heat-compressing the rubber, The material does not invade the cavity between the strands, and it is a composite that simply wraps the cord with the rubber sheet, and the rubber material completely penetrates into the cavity between the cord strands. Does not become a so-called perfect composite. Therefore, when a composite sheet obtained by compressing a conventional closed twisted cord sandwiched between rubber sheets is incorporated into, for example, an automobile tire, the adhesion between the rubber material and the cord is insufficient, and the rubber material peels off from the cord when the automobile is running. In other words, there is a high possibility of causing a so-called separation phenomenon, and when the moisture that has penetrated into the rubber material reaches the cavity of the cord, the moisture propagates along the cavity and in the longitudinal direction of the cord and corrodes the cord. As a result, the mechanical strength of the cord is significantly reduced.

  Also, as shown in FIG. 6, a group of strands (referred to as “core strand group”, including the case of a single strand) constituting the central layer of the three-layer structure cord 60, and an intermediate layer. The caulking for twisting applied to the strands 61, 62, 63 of the strand group (referred to as “intermediate strand group”) and the strand group constituting the outer layer (referred to as “side strand group”). A cord having an open twist structure in which a rubber material is easily invaded by providing a gap 64 communicating with the outside between the strands 61, 62, 63 by making it excessive is also known. However, the cord of the open stranded structure has no contact between the core strand group and the intermediate strand group, and the intermediate strand group and the side strand group do not contact each other. The strand group is easy to move and the twist stability is low.

  In addition, as shown in FIG. 7, in the cord 70 having a three-layer structure, the core strand group, the intermediate strand group, and the side strand group are each composed of a predetermined number of strands 71, 72, 73, and the central strand group Alternatively, it has a small helical comb different from the twist for twisting a part of the intermediate strands (in the illustrated example, three of the nine strands 72 of the intermediate strands are included in three strands). A case in which a helical habit is provided is shown.) A proposal has been proposed (for example, see Patent Document 1). The cord 70 communicates with the outside between a strand 72 having a spiral bend (referred to as “spiral strand”) and a strand not provided with a spiral bevel (referred to as “non-spiral strand”). A gap 74 is formed and the rubber material enters. The strand 71 of the core strand group engages with any strand 72 of the intermediate strand group, and the strand 72 of the intermediate strand group engages with any strand 73 of the side strand group. Therefore, there is no degree of freedom in the cord longitudinal direction of the core strand group and the intermediate strand group, and no shift movement in the cord longitudinal direction occurs.

  However, the conventional cords in which the spiral strands are provided on the strands of the core strand group or the intermediate strand group in this way are those in which only some strands are spiral strands, and non-spiral strands A portion surrounded by each other becomes a closed cavity, and the rubber material does not enter there.

  Therefore, as shown in FIG. 8, in the cord 80 having a three-layer structure, the core strand group, the intermediate strand group, and the side strand group each include a predetermined number of strands 81, 82, and 83. It is conceivable that all the strands 82 of the line group are spiral strands. By doing so, the gap 84 communicating with the outside is enlarged, and the closed cavity is eliminated. However, if all the strands 82 of the intermediate strand group are spiral strands as described above, the elongation of the cord becomes large, which becomes a new problem. The cord needs to be stretched to some extent in order to obtain flexibility. However, if the cord is stretched more than necessary, the rigidity of the tire is lowered. In particular, a cord used for a carcass portion of a tire that is becoming steel in recent years is not suitable for a cord having a large low load elongation because the running stability of the tire is lowered.

JP 2000-80578 A

  Accordingly, a rubber cord for reinforcing a rubber product having a three-layer structure having a good rubber material penetration property, no twist movement of the core strand group and intermediate strand group, a stable twisted structure, and a small low load elongation is obtained. This is a problem.

  The above-mentioned problem is a steel cord having a three-layer structure of L + M + N (L = 1 to 4, M = 4 to 9, N = 8 to 15) or a bundle twist three-layer structure of 1 × P (P = 13 to 27). There is a gap between at least some of the strands of the strand group constituting the outer layer, and all the strands of the strand group constituting the intermediate layer are separated from the habit for twisting. At least one strand of the strand group constituting the intermediate layer has a central layer in almost all locations in the longitudinal direction of the cord having a pitch smaller than the twist for twisting. The problem can be solved by making contact with at least one strand of the strand group to be configured.

  This cord is used for twisting the strands of the strands constituting the intermediate layer (intermediate strands) by the rubber material that has entered through the gaps between the strands of the strands constituting the outer layer (side strands). The intermediate strand group and the strand group constituting the central layer (core strand group) enter from a gap formed between strands having a pitch smaller than the comb. In addition, this cord has a structure in which all the strands of the intermediate strand group have a pitch smaller than the pitch for twisting, so that the intermediate strand group is located between the intermediate strand group and the side strand group. There is no closed cavity between the core wire group and the core wire group. Therefore, the rubber material easily enters.

  In this cord, since at least any one strand of the intermediate strand group is in contact with at least one strand of the core strand group in almost all locations in the cord longitudinal direction. The intermediate strand group and the core strand group are continuously engaged in the cord longitudinal direction, and the strands of the intermediate strand group are also partially engaged with the strands of the side strand group. Therefore, the intermediate strand group does not shift in the longitudinal direction of the cord, and the twist is stabilized.

  Further, in this cord, since at least any one strand of the intermediate strand group is in contact with at least any one strand of the core strand group at almost all locations in the cord longitudinal direction. Like the closed twisted cord, the elongation of the cord is small and low load elongation can be suppressed.

  In addition, the above-mentioned problem is that a three-layer twist structure of L + M + N (L = 1 to 4, M = 4 to 9, N = 8 to 15) or a bundle twist three-layer structure of 1 × P (P = 13 to 27). The steel cord has a gap between at least some of the strands of the strand group constituting the outer layer, and all strands of the strand group constituting the intermediate layer are twisted for twisting together. In addition, there is a pitch smaller than the twist for twisting, and the wires of the wire group constituting the intermediate layer come into contact with each other in substantially parallel so that the wires are substantially parallel to the cord central axis. The part where the difference between the strand angle of the strands of the strand group constituting the layer and the strand angle of the strand group constituting the outer layer is partially present in a discontinuous arrangement in the cord longitudinal direction This configuration can solve the problem.

  This cord is used for twisting the strands of the strands constituting the intermediate layer (intermediate strands) by the rubber material that has entered through the gaps between the strands of the strands constituting the outer layer (side strands). The intermediate strand group and the strand group constituting the central layer (core strand group) enter from a gap formed between strands having a pitch smaller than the comb. In addition, this cord has a structure in which all the strands of the intermediate strand group have a pitch smaller than the pitch for twisting, so that the intermediate strand group is located between the intermediate strand group and the side strand group. There is no closed cavity between the core wire group and the core wire group. Therefore, the rubber material easily enters.

  And this cord is contacted in approximately parallel so that the strands of the intermediate strand group are substantially parallel to the cord central axis, and the strand angle of the strand of the intermediate strand group and the strand of the side strand group The part where the difference from the twist angle becomes larger is partly discontinuously arranged in the longitudinal direction of the cord, preventing the strands of the side strands from falling due to the uniform twist angle and intruding the rubber material A road is secured.

  Further, in this cord, the strands of the intermediate strand group are partially engaged with the strands of the side strand group, and the strands of the core strand group are substantially the same in the longitudinal direction of the cord. Since at least one strand of the intermediate strand group is in contact with at least one strand of the core strand group, the intermediate strand group and the core strand group are arranged in the longitudinal direction of the cord. As a result, the intermediate strand group is not displaced in the longitudinal direction of the cord, and the twist is stabilized. Further, in this cord, since the strands of the intermediate strand group come into contact with the strands of the core strand group, the cord has a small elongation and can suppress a low load elongation.

  In addition, the above-mentioned problem is that a three-layer twist structure of L + M + N (L = 1 to 4, M = 4 to 9, N = 8 to 15) or a bundle twist three-layer structure of 1 × P (P = 13 to 27). The steel cord has a gap between at least some of the strands of the strand group constituting the outer layer, and all strands of the strand group constituting the intermediate layer are twisted for twisting together. In addition, at least one strand of the strand group constituting the intermediate layer has a pitch smaller than the twist for twisting, and at almost all locations in the longitudinal direction of the cord, The wires in contact with at least one of the wires constituting the layer are in contact with each other so that the wires in the wires constituting the intermediate layer are substantially parallel to the cord central axis. The strands of the strands of the strands constituting the intermediate layer and the outer layer Point the difference between the twist angle of the strands of the strand group is large, it can be solved by constructing so that partially present in the code longitudinally discontinuous arrangement.

  This cord is used for twisting the strands of the strands constituting the intermediate layer (intermediate strands) by the rubber material that has entered through the gaps between the strands of the strands constituting the outer layer (side strands). The intermediate strand group and the strand group constituting the central layer (core strand group) enter from a gap formed between strands having a pitch smaller than the comb. In addition, this cord has a structure in which all the strands of the intermediate strand group have a pitch smaller than the pitch for twisting, so that the intermediate strand group is located between the intermediate strand group and the side strand group. There is no closed cavity between the core wire group and the core wire group. Therefore, the rubber material easily enters.

  And this cord is contacted in approximately parallel so that the strands of the intermediate strand group are substantially parallel to the cord central axis, and the strand angle of the strand of the intermediate strand group and the strand group constituting the outer layer Since the part where the difference with the strand angle of the strand is large is partially present in a discontinuous arrangement in the cord longitudinal direction, the falling of the strands of the side strand group due to the uniform twist angle is prevented, A rubber entry path is secured.

  Furthermore, in this cord, at any location in the longitudinal direction of the cord, at least one strand of the intermediate strand group always contacts one of the strands of the core strand group. The strands partially engage with the strands of the side strand group. Therefore, the intermediate strand group does not shift in the longitudinal direction of the cord, and the twist is stabilized.

  In addition, in this cord, at almost all locations in the longitudinal direction of the cord, at least one strand of the intermediate strand group contacts at least one strand of the strand group constituting the center layer. Therefore, the elongation of the cord is small as in the case of the closed twist cord, and the low load elongation can be suppressed.

  In the cord having the above-described configuration, the habit having a smaller pitch than the habit for twisting is preferably a habit obtained by pressing a strand after forming a helical habit on the strand. Even if a wire is passed between a pair of gears whose teeth have been processed into a desired shape, a small wrinkle can be obtained by bending the wire into a zigzag shape. The degree of work becomes greater than the part where there is not, stress remains in the bent part where the degree of work is large, and stress due to external force is added to this, so that the stress at the bent part becomes excessive and the fatigue resistance decreases. On the other hand, the wrinkle obtained by applying a pressurizing process after applying a helical wrinkle has an even degree of processing at any location, so that excessive stress does not act and it has excellent fatigue resistance. Become.

  Further, the pitch P1 is P1 = 0.2Pc to 0.5Pc (where Pc is the pitch of twisting) and the wave height h is h = 0.2d to It is preferably 1.2d (where d is the wire diameter). If the pitch P1 is smaller than 0.2 Pc, excessive plastic deformation is applied to cause excessive stress at the time of soldering, so that the strands are easily broken and the productivity is lowered, and the pitch P1 is less than 0.5 Pc. If it is large, the tensile force is not evenly applied, and the twist stability of the intermediate strand group is deteriorated and the fatigue resistance is deteriorated. Also, if the wave height h is less than 0.2d, the gap between the wires becomes too small, and even if a rubber material with good fluidity is used, the rubber material can sufficiently penetrate into the interior during pressure vulcanization. If the wave height h is greater than 1.2 dmm, the twist stability is deteriorated and the fatigue resistance is deteriorated. Note that the values of the pitch P1 and the wave height h, which have a smaller pitch than the twists for twisting, coincide with those of the strands obtained by untwisting the cord.

The steel cord for reinforcing rubber products of the present invention can be manufactured by the following method.
That is, in the case of a steel cord having a three-layer twisted structure of L + M + N (L = 1 to 4, M = 4 to 9, N = 8 to 15), a strand constituting the central layer by twisting L strands M, which is a two-dimensional wave shape obtained by pressing a strand after forming a spiral bevel on the strands constituting the central layer and having a pitch smaller than the twist for twisting The strands of the strands constituting the intermediate layer by twisting the strands of the strands, and the strands of N wires so that a gap exists between at least some strands on the strands of the strand constituting the intermediate layer The steel cord of the present invention can be manufactured by applying a pressing process from the direction orthogonal to the cord longitudinal direction to the steel cord having the three-layer twist structure formed in this manner.

  In addition, in the case of a steel cord having a 1 × P (P = 13 to 27) bundle-twisted three-layer structure, all the strands of the strand group constituting the intermediate layer are subjected to a pressing process after adding a helical comb. An intermediate layer group consisting of strands having a substantially two-dimensional corrugated shape and a pitch smaller than the twist for twisting, and a core layer strand The strands of the strands of the group and the outer layer are twisted at once in the same direction and at the same pitch to form a bundle-twisted three-layer steel cord in which a gap exists between at least some of the strands of the outer layer And the steel cord of this invention can be manufactured by giving a pressing process to this steel cord from the direction orthogonal to a cord longitudinal direction.

  In this way, a steel cord having a three-layer twist structure is formed by twisting the strands of the intermediate strand group having a substantially two-dimensional wavy habit on the core strand group and further twisting the strands of the side strand group. By pressing from the direction orthogonal to the longitudinal direction of the cord, the strands of the intermediate strand group consisting of strands having a substantially two-dimensional undulation, the core strand group and the side strand group are twisted at once. By applying a pressing process to the steel cord having a bundle-twisted three-layer structure formed in a direction orthogonal to the longitudinal direction of the cord, at least any one strand of the intermediate strand group in almost all the locations in the longitudinal direction of the cord Is a cord that is always in contact with at least one strand of the core strand group, and in parallel so that the strands of the intermediate strand group are substantially parallel to the cord center axis. The strand angle and outer layer of the strands of the intermediate strand group Point the difference between the twist angle of the strand of the strand group to be formed becomes large, the code present partially in discontinuous located in code longitudinally.

  In these manufacturing methods, the strands of the intermediate strand group are wound with a helical wrinkle, then pressed and wound into a reel, etc., and then rolled out by a twisting machine. A predetermined number of wires may be set and twisted together in the device, or the kneading process may be performed between the twisting device and the twisting port.

  According to the present invention, for rubber product reinforcement with a three-layer structure that has good rubber material penetration, no twist movement of the core strand group and intermediate strand group, stable twist structure, and low low load elongation A steel cord can be obtained, and the life of the tire can be greatly extended by using this cord as a reinforcing material for an automobile tire, for example. In addition, since the low load elongation is small, this cord can be used for a carcass portion of a tire that is becoming steel.

  In addition, this cord is made by making a habit with a smaller pitch than the habit for twisting the strands of the intermediate strand group, and a habit obtained by pressing the strand after adding a helical habit to the strand. Further, the degree of processing becomes uniform, excessive stress does not act, and excellent fatigue resistance can be achieved.

  Also, this cord is in the state of the strand after untwisting, and the pitch P1, which is smaller than the twist for twisting, is P1 = 0.2Pc to 0.5Pc (where Pc is twisted) In this case, it is possible to avoid excessive plastic deformation and increase productivity, and to prevent the twist stability and fatigue resistance of the intermediate strand group from being deteriorated. . Further, in the state of the strands after untwisting the strands, the wave height h of the pitch having a smaller pitch than the strand for twisting is h = 0.2d to 1.2d (where d is the strand diameter). By doing so, the rubber material can sufficiently penetrate into the inside, and the stability of twisting and fatigue resistance can be prevented from deteriorating.

  Hereinafter, a steel cord for reinforcing rubber products according to an embodiment of the present invention (hereinafter referred to as “steel cord” or simply “cord”) will be described with reference to the drawings.

  FIG. 1 shows a cross-sectional structure of a steel cord having a 1 + 5 + 11 structure as an example of an embodiment of a steel cord having a three-layer twist structure of L + M + N (L = 1 to 4, M = 4 to 9, N = 8 to 15). ing.

  The cord (steel cord) 10 shown in FIG. 1 has a 1 + 5 + 11 three-layer twisted structure, and has a small sine wave around a single strand (core strand 11) (pitch more than the strand for twisting). 5 strands (intermediate strands 12) having small habits are twisted, and 11 strands (side strands 13) having only a habit for twisting are twisted outside (outermost). The cord having the three-layer twisted structure thus formed is pressed from the direction orthogonal to the cord longitudinal direction.

  The cord 10 includes a gap 14 between at least some of the strands (side strands 13) of the strand group constituting the outer layer, and a strand group (intermediate strand group) constituting the intermediate layer. All of the strands (intermediate strands 12) are substantially two-dimensional wavy apart from the twist for twisting, and have a pitch and a pitch smaller than the twist for twisting. This substantially two-dimensional wave-like habit is a habit obtained by applying a helical wrinkle to an element wire (intermediate element wire 12) and then pressing it. In the state of the element wire before twisting, it is substantially sinusoidal. is there.

  The substantially sinusoidal habit of the strands before twisting means the length (period) P1 from the wave valley to the valley or from the mountain to the mountain as shown in FIG. 3, and the wave height is from the wave valley to the mountain. Means the height (amplitude) h. The intermediate wire 12 has a substantially two-dimensional wavy pitch P1 of P1 = 0.2Pc to 0.5Pc (where Pc is a twisted pitch) and a wave height h of h = 0.2d to 1.d. 2d (where d is the wire diameter). In addition, it is preferable that the strand diameter d is 0.15-0.40 mm. If it is less than 0.15 mm, the strength of the steel cord is lowered, and if it exceeds 0.40 mm, the flexibility is deteriorated.

  The cord 10 has at least one strand of the strands of the intermediate strand group (intermediate strand 12) in the central portion of the cord longitudinal direction as shown in FIG. Contact with the strands (core strands 11) of the strand group (core strand group) to be configured (when there are a plurality of core strands 11 of the core strand group), contact with at least one of the core strands 11 Contact).

  In addition, as shown in FIG. 4, the cord 10 includes a group of intermediate strands (intermediate strands 12) which are in contact with each other in a discontinuous arrangement in the longitudinal direction of the cord and partially in parallel. Of the strand (side strand 13) of the strand group (side strand group) constituting the outer layer (not shown), where the twist angle α of the intermediate strand 12 is 0 (zero). The difference from the twist angle (same as the twist angle α in the non-parallel portion of the intermediate strand 12) is large.

  On the core strand 11 (core strand group), a plurality of intermediate strands 12 (five in the example shown in the figure) having a small sine wave shape are placed at almost all locations in the longitudinal direction of the cord. When the strands 12 are twisted so that at least one of the strands 12 comes into contact with the core strand 11, the plurality of intermediate strands 12 are periodically blended at predetermined intervals in the longitudinal direction of the cord. The portion having the twist angle α and the portion in contact with each other in a substantially parallel fashion are formed, and a twisted structure as shown in FIG. 4 is obtained.

  In the cord 10, a rubber material that has entered from a gap 14 between the strands of the side strand group (side strand 13) has a strand (intermediate strand 12) having a small two-dimensional wavy shape of the intermediate strand group. ) It enters between the intermediate strand group and the core strand group from the gap 15 formed between them. In addition, the cord 10 has an intermediate wire group between the intermediate wire group and the side wire group because all the wires (intermediate wire 12) of the intermediate wire group have a small two-dimensional wavy shape. There is no closed cavity between the strand group and the core strand group. Therefore, the rubber material easily enters.

  The cord 10 is brought into contact with each other in a substantially parallel manner so that the strands of the intermediate strand group (intermediate strands 12) are substantially parallel to the cord central axis. ) And the strand angle of the strands of the strands constituting the outer layer are partially discontinuously arranged in the longitudinal direction of the cord. The strands of the strand group (side strands 13) are prevented from dropping, and a rubber material intrusion path is secured.

  Further, the cord 10 includes at least any one strand of the intermediate strand group (intermediate strand 12) at least any one strand of the core strand group at almost all locations in the cord longitudinal direction. The core wires 11 are always in contact with each other, and the strands of the intermediate strand group (intermediate strands 12) are also partially engaged with the strands of the side strand group (side strand 13). Therefore, the intermediate strand group does not shift in the longitudinal direction of the cord, and the twist is stabilized.

  FIG. 2 shows a cross-sectional structure of a 1 × 16 bundle-twisted three-layer steel cord as an example of an embodiment in the case of a 1 × P (P = 13-27) bundle-twisted three-layer steel cord. ing.

  The cord (steel cord) 20 shown in FIG. 2 has a 1 × 16 bundle-twisted three-layer structure, with a single strand (core strand 21) as the center and a small sinusoidal twist (twisting together) around it. 5 strands (intermediate strands 22) having a pitch smaller than that of the forehead are disposed, and 10 strands (side strands 23) are disposed on the outside (outermost) at a time. The cords of the bundle-twisted three-layer structure formed by twisting are subjected to pressing from the direction orthogonal to the cord longitudinal direction.

  The cord 20 includes a gap 24 between at least some of the strands (side strands 23) of the strand group constituting the outer layer, and a strand group (intermediate strand group) constituting the intermediate layer. All of the strands (intermediate strands 22) are substantially two-dimensional wavy apart from the twist for twisting, and have a pitch and a wave height smaller than the twist for twisting. This substantially two-dimensional wave-like wrinkle is a habit obtained by adding a helical wrinkle to an element wire (intermediate element wire 22) and then pressing it. In the state of the element wire before twisting, it is substantially sinusoidal. is there.

  In the case of this cord 20 as well, the substantially sinusoidal habit of the intermediate strand 22 before twisting is such that the pitch P1 is P1 = 0.2 Pc to 0.5 Pc (where Pc is twisted) as shown in FIG. Pitch) and the wave height h is h = 0.2d to 1.2d (where d is the wire diameter). In addition, it is preferable that the strand diameter d is 0.15-0.40 mm. If it is less than 0.15 mm, the strength of the steel cord is lowered, and if it exceeds 0.40 mm, the flexibility is deteriorated.

  The cord 20 also has at least one strand of the strand of the intermediate strand group (intermediate strand 22) in the central portion of the cord longitudinal direction as shown in FIG. Contact with the strands (core strands 21) of the constituent strand group (core strand group) (in the case where there are a plurality of core strands 21 of the core strand group), at least one of the core strands 21 Contact).

  As shown in FIG. 4, the cord 20 is also configured such that the strands of the intermediate strand group (intermediate strands 22) are in contact with each other in a partially discontinuous arrangement in the longitudinal direction of the cord, and are substantially parallel. Of the strand (side strand 23) of the strand group (side strand group) constituting the outer layer (not shown) when the twist angle α of the intermediate strand 22 is 0 (zero). The difference from the twist angle (same as the twist angle α in the non-parallel portion of the intermediate strand 22) is large.

  Around the core strand 21 (core strand group), a plurality of intermediate strands 22 (five in the example shown in the figure) having a small sine wave shape are arranged, and the side strands are arranged outside (outermost). 23, and twisting at a time so that at least one of the intermediate strands 22 is in contact with the core strand 21 at almost all locations in the longitudinal direction of the cord, the plurality of intermediate strands 22 are In addition, a portion having a predetermined twist angle α that is adapted to periodically in the longitudinal direction of the cord to a predetermined twist angle α and a portion in contact with each other in a substantially parallel manner can be formed, resulting in a twist structure as shown in FIG. It is.

  In the cord 20, a rubber material that has entered through a gap 24 between the strands of the side strand group (side strands 23) has a substantially two-dimensional wave-like strand of the intermediate strand group (intermediate strand 22). ) It enters between the intermediate strand group and the core strand group from the gap 25 formed between them. In addition, since all the strands (intermediate strands 22) of the intermediate strand group have a small two-dimensional wavy shape, this code 20 is provided between the intermediate strand group and the side strand group and between There is no closed cavity between the strand group and the core strand group. Therefore, the rubber material easily enters.

  The cord 20 is brought into contact with each other in a substantially parallel manner so that the strands of the intermediate strand group (intermediate strands 22) are substantially parallel to the cord central axis. ) And the strand angle of the strands of the strands constituting the outer layer are partially discontinuously arranged in the longitudinal direction of the cord. The strands of the strand group (side strands 23) are prevented from dropping, and a rubber material entry path is secured.

  Further, the cord 20 is configured such that at almost any position in the longitudinal direction of the cord, at least one strand of the intermediate strand group (intermediate strand 22) is at least one strand of the core strand group. The core wires 21 are always in contact with each other, and the strands of the intermediate strand group (intermediate strands 22) are also partially engaged with the strands of the side strand group (side strands 23). Therefore, the intermediate strand group does not shift in the longitudinal direction of the cord, and the twist is stabilized.

  As an example, a steel wire having a diameter of 5.5 mm was repeatedly subjected to patenting and wire drawing, and then the surface was subjected to brass plating to form a strand having a wire diameter of 0.25 mm. Using this strand, 1 + 5 + 11 Two types of cords having a three-layer twisted structure and a 1 × 16 bundle-twisted three-layer structure were manufactured.

  In the cord of the embodiment of the 1 + 5 + 11 structure, the five strands as the intermediate strand group are each formed with a helical wrinkle and then subjected to pressing to form a small sinusoidal wrinkle (pitch from a twist for twisting). The strands are processed into strands, and the 5 strands are twisted around one core strand to form an intermediate strand group, and 11 strands (outermost) Side cords) are twisted together to form a cord with a three-layer twist structure, and the cord thus formed is manufactured by pressing from the direction perpendicular to the longitudinal direction of the cord.

  In addition, the cord of the embodiment of the 1 × 16 structure is formed by attaching a spiral bead to each of the five strands that are the intermediate strand group, and then pressing the press-work to form a small sinusoidal warp (for twisting). 5 strands (intermediate strands) having small sine wave-like small bends around one strand (core strand). Then, ten strands (side strands) are arranged on the outside (outermost) and twisted at once, and the cord of the bundle-twisted three-layer structure thus formed is pressed from the direction orthogonal to the cord longitudinal direction. Manufactured.

  In any case, the helical wrinkle was applied using a wrinkle device (a wrinkle device described in Japanese Patent Publication No. 63-63293, etc.) that rotates using the supplied strand as an axis. The comb shape was adjusted by the spacing of the tacking pins, the dimension of the tacking pins, and the number of rotations rotating around the element wire.

  In addition, the pressing process for processing the helical wrinkle into a substantially two-dimensional waved wrinkle and the pressing process after the stranded wire processing were performed by a known press processing device in which a plurality of freely rotating rollers were arranged in a staggered manner. . However, the pressing means is not limited to this.

  The rubber penetration, low load elongation and stability of the twisted structure of the cords of the examples manufactured in this way were evaluated in comparison with the cords of the conventional examples.

  For rubber penetration, each cord is embedded in a rubber material under a tensile load of 2 kg, and after pressure vulcanization, the cord is taken out, the cord is disassembled and a certain length is observed, and the observed length The ratio of the length of traces in contact with rubber to the percentage was evaluated as a percentage.

  The low load elongation was evaluated by expressing the elongation at the time of 5 kg load as a percentage.

  Further, as shown in FIG. 5, the stability of the twisted structure is such that a pair of sandwiching tools 31 and 32 provided with semicircular grooves having a depth substantially equal to the radius of the cord C are aligned vertically. When the cord 33 is placed on the upper pinching tool 31 and the cord C is continuously pulled out in one direction (in the direction of the arrow), the side wire of the cord C is excessively pinched. Evaluation was made as to how much amount (extra amount) the strands accumulated on the entrance sides of the grooves 31 and 32. If there is no excess amount, it means that the wire groups of each layer are in close contact with each other.

  In a conventional example, a steel wire having a diameter of 5.5 mm is subjected to patenting and wire drawing, and then subjected to plus plating on the surface to obtain a strand having a wire diameter of 0.25 mm. 1 + 5 + 11 closed structure cord, 1 + 5 + 11 open structure cord, 1 + 5 + 11 cord with a spiral wrinkle arranged in the middle layer, 1 × 16 open structure cord, 1 × 16 closed structure cord Six types of cords were manufactured, in which 1 × 16 strands having a helical wrinkle were arranged in the intermediate layer. The number of strands on which the spiral combs are provided is three of the five strands located in the intermediate layer for both the 1 + 5 + 11 structure cord and the 1 × 16 cord.

表１から、実施例のコードは全ての評価で従来コードより優れていることが明らかである。 The evaluation results are shown in Table 1.

From Table 1, it is clear that the code of the example is superior to the conventional code in all evaluations.

It is sectional drawing of the steel cord of the 1 + 5 + 11 3 layer twist structure of embodiment of this invention. It is sectional drawing of the steel cord of 1 * 16 bundle twist 3 layer structure of embodiment of this invention. It is explanatory drawing of the pitch and wave height of the substantially sinusoidal habit in embodiment of this invention. It is explanatory drawing of the twist structure of the intermediate | middle strand group in embodiment of this invention. It is explanatory drawing of the method of evaluating the stability of the twist structure of the steel cord of an Example. It is sectional drawing of the steel cord of the conventional 1 + 6 + 12 3 layer open twist structure. FIG. 6 is a cross-sectional view of a steel cord having a conventional 1 × 24 bundle-twisted structure in which some strands of an intermediate layer have a spiral bend different from the bend for twisting. It is sectional drawing of the code | cord | chord which has the helical habit different from the habit for twisting all the strands of the intermediate | middle layer by the conventional 1x24 bundle twist structure.

Explanation of symbols

10, 20 cord (steel cord)
11, 21 Core strands 12, 22 Intermediate strands 13, 23 Side strands 14, 24 Gap

Claims (7)

A steel cord of L + M + N (L = 1 to 4, M = 4 to 9, N = 8 to 15) or a three-layer twist structure of 1 × P (P = 13 to 27), There is a gap between at least some of the strands of the strands that make up the outer layer, and all strands of the strands that make up the intermediate layer are twisted separately from the twist for twisting And at least one strand of the strand group constituting the intermediate layer constitutes the central layer at almost all locations in the longitudinal direction of the cord. A steel cord for reinforcing rubber products, wherein the steel cord is in contact with at least one of the strands. A steel cord of L + M + N (L = 1 to 4, M = 4 to 9, N = 8 to 15) or a three-layer twist structure of 1 × P (P = 13 to 27), A gap exists between at least some of the strands of the strands that make up the outer layer, and all strands of the strands that make up the intermediate layer are twisted separately from the twist for twisting The intermediate layer is formed by contacting the wires in the group of wires constituting the intermediate layer substantially in parallel with each other so as to be substantially parallel to the cord central axis. The location where the difference between the strand angle of the strands of the strand group and the strand angle of the strands of the strand group constituting the outer layer is partially present in a discontinuous arrangement in the cord longitudinal direction Steel cord for reinforcing rubber products. A steel cord of L + M + N (L = 1 to 4, M = 4 to 9, N = 8 to 15) or a three-layer twist structure of 1 × P (P = 13 to 27), There is a gap between at least some of the strands of the strands that make up the outer layer, and all strands of the strands that make up the intermediate layer are twisted separately from the twist for twisting And at least one strand of the strand group constituting the intermediate layer constitutes the central layer at almost all locations in the longitudinal direction of the cord. While contacting at least one of the strands of the strand group, the strands of the strand group constituting the intermediate layer are substantially parallel to each other so that the strands are substantially parallel to the cord center axis. Strand angle of the strands constituting the layer and the strands of the strands constituting the outer layer Rubber products reinforcing steel cord for the difference between the twist angle is larger portion, characterized in that the partially present in discrete located in code longitudinal. The steel cord for reinforcing a rubber product according to claim 1, 2 or 3, wherein the habit having a smaller pitch than the habit for twisting is a habit obtained by pressing a strand after forming a helical habit on the strands. . The pitch smaller than the twist for twisting is such that the pitch P1 is P1 = 0.2 Pc to 0.5 Pc (where Pc is the twisting pitch), and the wave height h is h = 0.2 d to 1. The steel cord for reinforcing rubber products according to claim 1, 2 or 3, wherein d is 2d (where d is a wire diameter). L + M + N (L = 1-4, M = 4-9, N = 8-15) manufacturing method of a steel cord having a three-layer twisted structure, in which a core layer is formed by twisting L strands A strand group is formed, and on the strand group constituting the center layer, a helical pitch is applied, and then a substantially two-dimensional wave shape obtained by pressing, and a pitch having a smaller pitch than the twist for twisting. The strands of the M wires are twisted together to form a strand group that constitutes the intermediate layer, and N strands are formed so that a gap exists between at least some strands on the strand group that constitutes the intermediate layer. A steel cord for reinforcing rubber products, characterized in that strands are twisted to form a strand constituting an outer layer, and the steel cord having the three-layer twist structure thus formed is pressed from a direction perpendicular to the longitudinal direction of the cord. Production method. 1 × P (P = 13 to 27) of a method of manufacturing a steel cord having a three-layer structure of bundle twist, and pressing all the strands of the strand group constituting the intermediate layer after forming a helical habit It is a substantially two-dimensional wave obtained by processing and has a smaller pitch than the twist for twisting. A steel cord having a bundle-twisted three-layer structure in which the strands of the strand group and the strands of the outer layer are twisted at the same time in the same direction and at the same pitch, and a gap exists between at least some of the strands of the outer layer A method of manufacturing a steel cord for reinforcing rubber products, characterized in that the steel cord is pressed from a direction orthogonal to the longitudinal direction of the cord.

Images